Now that PU is being replaced by PUP, the current PU SN stuff is becoming a feverishly sought after collector's item due its extremely low Noack. But that's just among the BITOG crowd. Most others won't know the difference, and most engines probably won't either.

IIRC the SM oil had a ton of additives and is probably great for a good cleaning. I know it turned black in my car after 300 miles and my car had never darkened the oil before. Must have found some dirt somewhere. I wouldn't hesitate to use it.

Now that PU is being replaced by PUP, the current PU SN stuff is becoming a feverishly sought after collector's item due its extremely low Noack. But that's just among the BITOG crowd. Most others won't know the difference, and most engines probably won't either.